The upwardly-opening box assembly associated with vehicles such as pickup trucks and the like have, for many years, employed a large plurality of stamped metal panels for defining the box. For example, in most instances the inner front and side panels of the box are stamped sheet steel members, and in most instances the bed of the box is also defined by one or more stamped sheetlike steel panels. Forming the box predominantly from stamped sheet steel panels, however, results in structural and economic factors which are less than desirable.
A principal disadvantage associated with using stamped sheet steel panels is the fact that such panels require use of a greater quantity of material than is optimally desired, and also ultimately results in the formed members having greater weight than desired, both of which are undesirable from the standpoint of the overall vehicle. More specifically, it is known that stamping involves forming a three-dimensional shape from a flat sheet steel of rather thin gauge, and during stamping the three-dimensional deformation of the sheet steel necessarily causes stretching of the steel, particularly at those locations which are subjected to the greatest three-dimensional deformation. This stretching can typically be in the range of from 8% to 10%, and the net effect is that the thickness of the sheet steel at the stretched locations can be significantly reduced by this degree. Such significant thickness reduction hence results in areas of the sheet being of significantly reduced strength, and hence these reduced strength areas can dictate and control the design of the overall stamped part, thereby requiring initial use of a sheet thickness greater than would otherwise be required so as to compensate for the thickness reduction caused by stretching.
Stamping large sheets to define large three-dimensional panels, such as for a vehicle box assembly, also often results in undesired surface stretch marks or blemishes in the finished product. The stamping operation also typically requires that the sheet be significantly oversized relative to the finished product so as to permit trimming of the sheet around the entire peripheral edge of the finished stamped member, and this hence results in significant waste.
A further and significantly disadvantageous factor associated with use of stamped sheet steel panels for vehicle box assemblies is the cost associated with the manufacture of the required stamping tools, and the significant number of such tools required to form the different stamped panels. Since the stamped panels defining the front and side walls of the box assembly, as well as the bed, are all of rather large size, the stamping tool required to form a single panel is necessarily large and complex, and hence extremely costly to manufacture. The complexity associated with such tooling is further increased by the fact that the side and front panels typically have reinforcing channels formed along the upper edges thereof, which channels define either inverted U-shaped configurations or sometimes even a closed hollow channel, whereby the stamping tooling for such shapes involves multiple stamping steps and hence is complex and expensive.
The cost of the stamping tooling is further exacerbated by the fact that each stamped part requires its own customized stamping tooling. For example, the front panel, the right side panel and the left side panel of the bed assembly all require their own customized tooling. Further, different tooling must be provided to permit manufacture of the right and left side panels for each different bed length. Needless to say, the overall net effect is that the tooling is not only extremely costly, but the tooling also requires significant floor space in the factory, and additional labor for operation thereof.
Several currently known constructions for vehicle box assemblies employing a significant number of stamped sheet steel panels are illustrated by FIGS. 1-4. In FIG. 1, a box assembly 10 as associated with a pickup truck employs right and left upright inner side panels 11 and 12, respectively, joined to an upright inner front panel 13. The bottom of the box assembly is closed by a generally horizontal bed 14 which, in this conventional construction, employs a multiple-piece construction defined predominantly by a center bed panel 15 which extends throughout the full length of the bed and has a width which generally corresponds to the transverse width between the wheel well openings. The bed regions forwardly and rearwardly of the wheel well openings are defined by separate small bed panel sections 16 and 17 which are rigidly joined, as by welding, to the center bed panel 15 and to the adjacent upright side panels. The rear of the bed assembly defines a conventional access opening which, in a known manner, is closed by a swingable tailgate. In this known construction of the bed assembly, each of the front panel, right side panel, left side panel and bed are formed as stamped steel sheet members, all different, and in fact the bed in this example is formed by a plurality (here five) of stamped members. The wheel well covers 18, which are also typically separate stampings, are welded to the respective side panel and to the bed during the assembly process. A box assembly having constructional features similar to that illustrated by FIG. 1 hence employs a large number of different stamped members, and accordingly requires large investment in tooling as well as significant factory space for production and assembly of such construction.
FIG. 2 illustrates another known construction of a box assembly which is virtually identical to the box assembly of FIG. 1 described above, except that the bed 14′ in FIG. 2 is constructed as a one-piece stamped panel having wheel well openings formed in opposite sides thereof, typically by means of a separate stamping operation, thereby eliminating the need for separate side bed panels. The construction of the box assembly of FIG. 2 is in all other respects generally similar to that illustrated by FIG. 1, and hence possesses generally the same structural and cost disadvantages.
Referring now to FIG. 3, there is illustrated improvements with respect to a box assembly for a pickup truck, which improvements are illustrated in greater detail in U.S. Pat. No. 6,644,721, owned by the Assignee hereof. The box assembly illustrated in FIG. 3 is constructed generally the same as the box assembly shown in FIG. 1 except that the center floor pan 15 in FIG. 3 is constructed as a one-piece roll-formed member which provides improved performance and weight reduction.
Considering also the box assembly illustrated in FIG. 4, this depicts another improved construction of the box assembly developed by the Assignee hereof. This improved box construction generally corresponds to the box construction of FIG. 2 except that the full-sized bed member 14′ is constructed as a roll-formed member, rather than as a stamped member. This roll-formed construction of the one-piece bed member, as disclosed in greater detail in Assignee's U.S. Pat. No. 6,128,815, has been successfully commercially adopted and is currently in use on models of pickup trucks currently being sold.
As a known alternative construction for the box assembly illustrated by FIG. 1, the side panel, the adjacent wheel well cover and adjacent front and rear side bed panels can be formed as a one-piece stamping, a different such stamping being required for each of the right and left sides of the box assembly. Such stamping, however, due to its size and complex three-dimensional shape, requires complex and costly tooling.
Accordingly, it is an object of this invention to provide improved roll-formed component parts for a box assembly, such as a roll-formed front panel and/or roll-formed side panels and/or a roll-formed bed panel, which component parts provide improved characteristics with respect to construction, assembly and cost efficiencies with respect to materials, assembly and tooling, and which at the same time retain or provide improved performance characteristics with respect to the assembled box assembly.
More specifically, the improved roll-formed components of the present invention are believed to provide the assembled box assembly with improvements with respect to reduction in overall weight, reduction with respect to overall usage of material, reduction with respect to material cost, simplification with respect to required assembly, handling and manipulation, significant reduction with respect to tooling costs, and an ability to utilize the same tooling to facilitate manufacture of multiple or different sized parts.
According to the present invention, in one embodiment thereof, there is provided an improved front panel for a vehicle bed assembly, which front panel is defined by a monolithic one-piece roll-formed steel sheet member having a desired three-dimensional configuration. The sheet steel member is roll-formed in the lengthwise direction thereof, which direction extends transversely across the front of the box assembly. The front panel has a roll-formed channel, preferably a closed tubular channel, extending along the upper edge thereof, which channel is roll-formed along one edge of the sheet steel during forming of the front panel. This closed tubular edge rail is preferably closed by a seam weld which extends lengthwise therealong, which seam weld can be efficiently performed simultaneous with and directly downstream of the roll-forming operation.
The improved roll-formed front panel, as aforesaid, is preferably provided with a generally flat ledge or shelf deformed horizontally from the upright front panel so as to extend transversely across the front of the box assembly.
This shelf is preferably disposed downwardly a small distance from the top rail, but is also positioned upwardly a substantial distance from the lower edge of the front panel, whereby the shelf can be successfully utilized to provide additional functions associated with use of the vehicle box assembly, such as accommodating the edge of a cover or divider platform.
The improved front panel, as aforesaid, is also preferably provided with one or more reinforcing ribs roll-formed therein and extending lengthwise thereof so as to provide the front panel with desired strength and rigidity while permitting usage of minimal thickness sheet steel.
As a desired variation, the improved roll-formed front panel, as aforesaid, can be provided with a front bed-supporting cross rail integrally and monolithically joined to the front panel along a lower horizontally extending edge thereof. The front panel and cross rail are formed as a continuous and monolithic one-piece member by being formed during a continuous roll-forming operation, with the cross rail being formed either generally planar with or in perpendicular relationship to the front panel during the roll-forming operation, with a 90° bend between the front panel and cross rail being formed either during the roll-forming operation or by means of a subsequent bending operation. The resultant monolithic one-piece construction eliminates the requirement that a wholly separate front cross rail be manufactured and handled, and also eliminates the necessity of having to create a series of spot welds between a lower flange on the front panel and a downwardly-turned front flange on the cross rail, the latter being a conventional construction.
This invention, as it relates to the front panel, also provides an improved manufacturing process for the front panel by permitting roll-forming of the front panel so as to facilitate forming of front panels of different lengths, by facilitating the simultaneous roll-forming of a closed rail or channel extending along the upper edge thereof, by facilitating seam welding of the top rail as it is formed on the roll former, prior to the panel being cut to length, and by facilitating the ability to integrally roll-form a front bed-supporting cross rail as part of the front panel.
The present invention, according to a second embodiment, relates to an improved inner side panel for a vehicle box assembly. The inner side panel is a monolithic one-piece member which is roll-formed in the lengthwise direction thereof, and is provided with a roll-formed channel extending along the upper edge. The channel may, if desired, be a closed tubular channel and may be seam welded along the length thereof. The roll-formed side panel is also preferably provided with a generally flat horizontal shelf roll-formed lengthwise thereof at a location spaced downwardly a small distance from the top rail. This shelf provides numerous possible functions, such as by permitting two-by-fours or the like to be supported thereon so as to span across the box assembly in raised relationship from the bed, or by permitting a tonneau cover to be attached thereto in downwardly spaced relation from the exposed top rail, or by permitting a removable platform or shelf to be supported on and extended between the shelves defined on the opposed inner side panels. The side panel is also preferably provided with ribs or channels roll-formed therein longitudinally throughout the length thereof to provide improved strength and rigidity, and hence permit use of minimal thickness sheet steel.
The improved roll-formed side panel of the present invention, as aforesaid, can be cut to any desired length during the roll-forming operation so that the same roll-forming tooling can readily accommodate side panels of different lengths. Further, by forming wheel well openings in the side panels utilizing separate stamping tooling which act on the side panels after the panels have been cut to length, the same roll-forming line can be used to form not only side panels of different lengths, but can also be used to form both the right and left side panels.
The improved roll-formed inner side panel of the present invention, as aforesaid, in accordance with a variation thereof, can be integrally and monolithically formed with an adjacent portion of the floor or bed, namely that portion which defines the wheel well opening. The bed portion and side wall panel can be substantially simultaneously roll-formed to define an integral and monolithic one-piece construction, and the forming of the wheel well opening and the bending of the floor portion relative to the side wall panel can be performed after the one-piece roll-formed construction is cut to length. Alternately, the forming of the opening and the subsequent bending of the floor portion relative to the side panel can be carried out in sequence during the roll-forming, prior to the cut-to-length operation.
The invention also relates to an improved manufacturing process for forming a side panel for a vehicle box which, as discussed above, is roll-formed to facilitate the forming of a top rail, a horizontal shelf and reinforcing ribs extending lengthwise of the roll-formed panel, to facilitate cutting of the roll-formed panel into any desired length, and to permit the same roll-formed tooling to be utilized for both right and left side panels as well as panels of different lengths. The process also permits simultaneous forming of multiple side panels, such as roll forming a pair of side panels in side-by-side relationship so as to be effectively mirror images of one another, thereby simultaneously providing right and left panels and at the same time facilitating the simultaneous stamping of the wheel well openings therein and the forming of the top rails thereon, which top rails are disposed along the outer edges of the roll-formed sheet, with the roll-formed sheet being split lengthwise thereof to facilitate the simultaneous forming of side-by-side panels.
The present invention, according to a further embodiment, comprises a monolithic, one-piece roll-formed center floor pan for disposition between the wheel wells of a vehicle box assembly. The improved floor pan has roll-formed raised channels of partial width extending along opposite side edges thereof, which raised partial channels have perpendicularly projecting edge flanges which protrude downwardly by an extent which significantly exceeds the height of the channels formed in the bed member. The edge flanges on the center floor pan abut and are welded to edge flanges associated with side panels which fill the regions disposed forwardly and rearwardly of the wheel well openings. The edge flanges on the center floor pan, at regions corresponding to the supporting cross rails, have recesses opening upwardly over part of the height thereof to accommodate the cross rails while still providing partial reinforcement in the regions of the floor pan disposed directly over the cross rails, thereby eliminating the need to provide deformations or recesses in the cross rail.
According to the present invention, there is provided an improved box assembly for a vehicle, such as a pickup truck, which box assembly employs a roll-formed bed or pan, as well as a roll-formed front panel as briefly summarized above, and which may additionally employ a roll-formed inner side panel, as also briefly described above. The roll-forming of the large panel members associated with the box assembly permits minimal usage of material in terms of both square footage of material as well as material thickness, thereby minimizing cost and weight of the box assembly, and results in panels of substantially uniform thickness throughout the longitudinal transverse directions thereof.
The use of roll-formed panels is also desirable since it permits the panels to be formed from high strength steel if desired, specifically sheet steel having a yield strength in the range of from about 50,000 psi to about 100,000 psi, which high strength steel is typically not feasible for use with large stamped panels.
Other objects and purposes of the invention will be apparent to those familiar with constructions and processes similar to those described herein upon reading the following specification and inspecting the accompanying drawings.
Certain terminology will be used in the following description for convenience in reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “upwardly” and “downwardly” will also be used in reference to the surfaces or parts associated with the box assembly which respectively project upwardly or downwardly when the box assembly is in its normal assembled position on a vehicle. The words “front” and “rear” will be used with reference to those directions which normally connotate the front and rear of a vehicle when the box assembly is mounted thereon. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the box assembly, or designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.